Host-terminal emulation program, a relay program, a host-terminal emulation method, a communication program, a communication method, and a client computer

Abstract

A host-terminal emulation program which permits secure host linkage communication between a host within a protected network and a client outside the network. The client establishes in advance a receiving connection with a relay device, for receiving data compliant to a second protocol (Step S 1 ). Subsequently, the client establishes a transmitting connection with the relay device, for transmitting data compliant to the second protocol (Step S 2 ), and transmits data to the relay device via the transmitting connection (Step S 3 ). The relay device converts the data to a first protocol (Step S 4 ), and transmits the converted data to the host (Step S 5 ). On completion of data processing by the host (Step S 6 ), the processing result is transmitted to the relay device by means of the first protocol (Step S 7 ). The processing result is converted to the second protocol in the relay device (Step S 8 ) and transferred to the client (Step S 9 ).

1. A computer-readable recording medium storing a host-terminal emulation program for a computer to function as a terminal that interacts with a host computer via a firewall and a relay device, the host computer communicating with the relay device using a first protocol, the firewall permitting the terminal to reach the relay device, not by using the first protocol, but by using a second protocol, the relay device providing conversion between the first and second protocols,
 wherein the host-terminal emulation program causes the computer to perform a process comprising: 
 establishing a new receiving connection with the relay device by using the second protocol immediately after a previous set of data is received from the relay device, regardless of whether another set of receive data is due or not due; 
 establishing a transmitting connection with the relay device by using the second protocol when data is to be transmitted to the host computer in response to an input operation; 
 transmitting, via the transmitting connection, data entered by the input operation to the relay device by means of the second protocol; and 
 receiving, from the relay device via the established new receiving connection, output data from the host computer by means of the second protocol. 
 
   
   
     2. The computer-readable recording medium according to  claim 1 , the process further comprising the step of establishing another new receiving connection with the relay device immediately upon expiration of a previously established receiving connection. 
   
   
     3. The computer-readable recording medium according to  claim 1 , wherein the second protocol is a protocol which the relay device uses to deliver contents by means of a Web server function thereof. 
   
   
     4. The computer-readable recording medium according to  claim 1 , wherein the second protocol is a protocol which permits a connection to be established and cut off each time a request and a response as a unit are performed, respectively. 
   
   
     5. The computer-readable recording medium according to  claim 1 , wherein when the receiving connection is established, a request is output to the relay device to request start of a function within the relay device to wait for reception of data from the host computer. 
   
   
     6. The computer-readable recording medium according to  claim 1 , wherein the computer generates identification information by which the computer can be uniquely identified on a network or receives the identification information generated by the relay device, and when the transmitting connection and the receiving connection are established with the relay device, the computer transmits a connection request including the identification information to the relay device. 
   
   
     7. A host-terminal emulation method for transferring data through a terminal that is connected to a host computer via a firewall and a relay device, the host computer communicating with the relay device using a first protocol, the firewall permitting the terminal to transfer data to the relay device, not by using the first protocol, but by using a second protocol, the relay device providing conversion between the first and second protocols, the host-terminal emulation method comprising:
 establishing a new receiving connection with the relay device by using the second protocol immediately after a previous set of data is received from the relay device, regardless of whether another set of receive data is due or not due; 
 establishing a transmitting connection with the relay device by using the second protocol when the data is to be transmitted to the host computer in response to an input operation; 
 transmitting, via the transmitting connection, the data entered by the input operation to the relay device by means of the second protocol; and 
 receiving, from the relay device via the newly established receiving connection, output data from the host computer by means of the second protocol. 
 
   
   
     8. The host-terminal emulation method according to  claim 7 , further comprising the step of establishing another new receiving connection with the relay device immediately upon expiration of a previously established receiving connection. 
   
   
     9. The host-terminal emulation method according to  claim 7 , wherein the second protocol is a protocol which the relay device uses to deliver contents by means of a Web server function thereof. 
   
   
     10. The host-terminal emulation method according to  claim 7 , wherein the second protocol is a protocol which permits a connection to be established and cut off each time a request and a response as a unit are performed, respectively. 
   
   
     11. The host-terminal emulation method according to  claim 7 , wherein when the receiving connection is established, a request is output to the relay device to request start of a function within the relay device to wait for reception of data from the host computer. 
   
   
     12. The host-terminal emulation method according to  claim 7 , wherein the terminal generates identification information by which the terminal can be uniquely identified on a network or receives the identification information generated by the relay device, and when the transmitting connection and the receiving connection are established with the relay device, the terminal transmits a connection request including the identification information to the relay device. 
   
   
     13. A data relay method for use by a relay device disposed between a firewall and a host computer to relay data between the host computer and a client computer located beyond the firewall, the data relay method comprising:
 communicating with the host computer by using a first protocol; 
 communicating with the client computer through the firewall by using a second protocol; 
 establishing a new connection with the client computer, immediately after relaying a previous set of data from the host computer to the client computer, regardless of whether another set of data is due or not due; and 
 relaying a new set of data from the host computer to the client computer via the established new connection after converting the new set of data from the first protocol to the second protocol. 
 
   
   
     14. A host-terminal device that interacts with a host computer via a firewall and a relay device, the host computer communicating with the relay device using a first protocol, the firewall permitting the host-terminal device to reach the relay device, not by using the first protocol, but by using a second protocol, the relay device providing conversion between the first and second protocols, the host-terminal device comprising:
 receiving connection establishing means for establishing a new receiving connection with the relay device by using the second protocol, immediately after a previous set of data is received from the relaying device, regardless of whether another set of receive data is due or not due; 
 transmitting connection establishing means for establishing a transmitting connection with the relay device by using the second protocol when data is to be transmitted to the host computer in response to an input operation; 
 transmitting means for transmitting, via the transmitting connection established by the transmitting connection establishing means, data entered by the input operation to the relay device by means of the second protocol; and 
 receiving means for receiving, from the relay device via the new receiving connection established by the receiving connection establishing means, output data from the host computer by means of the second protocol. 
 
   
   
     15. A relay device disposed between a firewall and a host computer to relay data between the host computer and a client computer located beyond the firewall, not by using a first protocol, but by using a second protocol, the relay device comprising:
 means for communicating with the host computer by using a first protocol; 
 means for communicating with the client computer through the firewall by using a second protocol; 
 means for establishing a new connection of the second protocol with the client computer, immediately after relaying a previous set of data from the host computer to the client computer, regardless of whether another set of data is due or not due; and 
 means for relaying a new set of data from the host computer to the client computer via the established new connection after converting the new set of data from the first protocol to the second protocol. 
 
   
   
     16. A computer-readable recording medium recording a relay program for use by a computer disposed between a firewall and a host computer to relay data between the host computer and a client computer separated by the firewall,
 wherein the relay program causes the computer to perform a process comprising: 
 communicating with the host computer by using a first protocol; 
 communicating with the client computer through the firewall by using a second protocol; 
 establishing a new connection of the second protocol with the client computer immediately after relaying a previous set of data from the host computer to the client computer, regardless of whether another set of data is due or not due; and 
 relaying a new set of data from the host computer to the client computer via the established new connection after converting the new set of data from the first protocol to the second protocol.